Electrical thermostatic alarm system.



A. GOLDSTEIN. ELECTRICAL THERMOSTATIG ALARM SYSTEM.

APPLICATION FILED MAY 2, 1910.

Patented Nov. 29, 1910 "UNITED STATES PATENT oFF oE.

ALBERT GOLDSTEIN, OF NEW YORK, N. Y., ASSIGNOR TO INTERNATIONAL ELECTRICPROTECTION COMPANY, A CORPORATION OF NEW YORK.

ELECTRICAL THERMOSTATIC ALARM SYSTEM;

Application filed May 2, 1910. Serial No. 558,819.

To all whom it may concern:

Be it known that I, ALBERT GOLDSTEIN, a citizen of the United States,residing at New York, in the county of New York and State of New York,have invented a certain new and useful Improvement in ElectricalThermostatic Alarm Systems, of which the following is a specification.

The invention relates to anelectrical thermostatic alarm system,..andhas forits object the prevention of false alarms, due to accidentaltroubles on the line.

The invention consists, first, in the combination whereby three changesmust be produced in the circuit, such as two breaks and a make, or twomakes and a break, before the alarm operates; and also in theconstruction of the thermostat whereby upon the movement of thediaphragm due to expansion of air within thecase, said changes arecaused. In this way, two accidental changes occurring on the line, suchas a crossing, and then a separation of the wiresdue, for example, tothe wires swinging together and then swinging apart-is prevented fromgiving a false alarm.

In the accompanying drawings-Figure 1 is a cross section of mythermostat, andFig. 2 is an electrical diagram of an alarmcircuitincluding three of said thermostats located at differentstations.

Similar letters and numbers ofreference indicate like parts.

The circular case 1' comprises two. flanged cup-shaped members 2, 3,between which the diaphragm 4 is received and held. Said diaphragm is tobe made of thin sheet metal, preferably the thinnest sheet copperprocurable, and may be corrugated and provided with a central contactboss 5'. The member 2 is to be preferably made of steel much heavierthan the member 3, so as to form the chief support for the device. Themember 3 is preferably of a metal that is highly con-' ductlve of heat,such as copper, and as thin as will afford the necessary rigidity Theflange of member 3 has a corrugationt which enters a similar corrugationin the flange of member 2. The flange of' diaphra m 4 is clamped betweensaid corru gate members, sothat the diaphragm is thus strained and aclose air-tight joint formed between the parts. The member '3: may besecured by bendin its circumferen ftial edge 7 overthe edge 0 member 2.

Specification of Letters Patent.

Patented Nov. 29, 1910.

8 of insulating material, on which are two contact plates 9, 10. In theblock is an opening' through which loosely passes a metal r0 11supported on ascrew 12, which passes through a metal bridge piece 13,which normally rests on the contact plates 9, 10. The bridge piece 13forms a nut for the screw 12 in which said screw may be adjusted byturning the milled head 14 so as to bring the lower end of rod 11 intodesired proxlmity to the boss 5 on diaphragm4. The contact plates 9,.10. are respectively connected to terminals of the circuit wire a,while thediaphragm 4 is connected to terminals of the Centrally disposedin member 2 is a block' the chamber therein on one side of the'diamunicating with an opening in the wall of said chamber.

The Q eration of the thermostat is as fol- 'lows: T e contact piece 11is first adjusted in suitable proximity to the diaphragm 4.'

When the surrounding atmosphere" increases in temperature, the heat israpidly conducted through the thin metal wall of the chamber in member 3and expands the air therein. This airv can escape only through the tube16 which is made long,

and of: small cross sectional area as compared with the vents 15, so asto retard the air flow. On the other hand, the air in-the' chamberinmember2 on theother side of the diaphragm can escape more freely-throughexpansion of the air in. the chamber canthe vents 15. The consequenceis, that the taming the tube is so quick as to be prac- 'tically animpulse in the confined/ai body which, being communicated to. thediaphragm 4, first moves it into contact with rod. 11-, thus producing acrossin from wire a' to wire 'a,-.and' then the furt er upwardmovementof the diaphragm raises the rod 11 and bridge-13, first, tobreak contact be- 1 tween the terminal lates 97.10, and then to closecontactwitht e contact piecesfzl).

In Fig. 2 the thermostat is shownin an alarm circuit.

The wires a, a are line conductors connected to opposite poles of thebattery A.

In the conductor a is a magnet B which controls the two switch levers band b.

.The battery current normally energizes magnet B, so that a metalliccircuit proceeds from one pole of battery A, by wire a, to magnet B, tocontact point 0, switch lever b, and wire a back to battery. In theconductor a and on opposite sides of the battery A are two magnets C, D,which respectively actuate pivoted armatures E, F, which areinbell-crank form. At the end of each vertical arm of the armatures E, F,

are formed Z-shaped slots 6, f, which receive pins G on the ends of thepivoted arms H. Said arms may fall by gravity to meet contact points 2',j, and so close a local circuit which includes a battery I and'electricbell J.

In the circuit conductors a, a at N, N, N are interposed as many of thethermostats, shown in Fig. 1, as there are stations from which it isdesired alarms shall be given. v

The operation is as follows: Assume the diaphragm of the thermostat atN, Fig; 2, to

drawing. The

breaking circuit in wire a at 9 and 10. Mag-' nets C and D then fail,and the armatures E, F return to the position shown in the pins G thendescend tothe second angle 1 1n slots 6 and f. The diaphragm stillcontinuing its movement car ries the bridge piece now out of'contact fortwo abnormal changes in the electricalconditions to actuate said alarm.In this way, false alarms from troubles on the line will be largelyprevented.

I claim:

1. The combination in circuit of an electrical thermostat comprising acase, a diaphragm in said case and operated by air,

expansion therein, means-controlled by said diaphragm for makingsuccessively three changes in the electrical condition of the circuit,and an alarm device operating only after the third change in saidcondition.

2. The combinationin circuit of an electrical thermostat comprising acase, a diaphragm in said case and operated by air expansion therein,means controlled by said diaphragm for first making, then breaking andthen making said circuit, and an alarm device operating only after saidsecond make.

3. The combination in circuit ofa magnet, a circuit closing switchcontrolled by said magnet to move over three successive portions of itspath before closing circuit, and an electrical thermostat comprising acase, a diaphragm in said case and operated by air expansion therein,and means actuated by said diaphragm to control said magnet to causesaid movement of said switch.

In testimony whereof I have aflixed my signature in presence of twowitnesses.

Y ALBERT GOLDSTEIN.

Witnesses:

GERTRUDE T. PORTER, MAY T. MOGARRY.

